THERE ARE MANY magical perks in the Harry Potter universe that we might want in our world, but we can be thankful that others stay firmly bound between book covers. Foremost among them: the Dementors, those floating wraiths made of mildew and hate who suck all the youthful life out of you like some malevolent spiritual vacuum cleaner.

Yet the real world does have its boogeymen ready to vanquish boy wonders, like that faceless but not ageless specter known only by a number. At Hogwarts it might have been known as the Quadraginus; in “All About Eve,” Bette Davis put it more bluntly: “Four-Oh.”

Rufus Wainwright, the perennially boyish singer-songwriter known for his plaintive poeticism, knows the fear. He is rapidly approaching his 40th birthday, in less than a month. Not one to hide under a barrel, the singer is planning to go over the falls in one instead, with plenty of fanfare and a high-profile celebration at the Royal Theater in Madrid, in what he described as “Rufus-avaganza.”

Even so, he’s worried. “Turning 40 is tricky,” Mr. Wainwright said, speaking from Toronto, where he and his husband, Jörn Weisbrodt, the German-born artistic director of the city’s Luminato Festival, primarily reside. (This week, Mr. Wainwright is in New York to pay homage to his late mother, the musician Kate McGarrigle, with two benefits at the Brooklyn Academy of Music: a screening of a film about her, “Sing Me the Songs That Say I Love You,” on Tuesday and a tribute concert on Wednesday.)

Back in January, Mr. Wainwright had a kind of dress rehearsal for the big changeover, courtesy of Mr. Weisbrodt’s 40th birthday, and in a deft maneuver, neatly managed to kill two birds with one stone-encrusted birthday present. In Los Angeles in December, Mr. Wainwright was visiting the Window, a modern furnishings store co-owned by his friend Lorca Cohen, the daughter of Leonard Cohen. (Mr. Wainwright is the father of Ms. Cohen’s 2-year-old daughter, Viva.) There he spotted a curious thing: a magic wand that, even as magic wands go, was way out of the ordinary: a 15-inch medieval-ish rod of solid bronze with a spiral pattern and set with quartz, amethyst and other crystals. It was what every wand dreams of becoming: a magic scepter.

“This isn’t a learn-magic-at-home kind of wand,” he said. “This is a beautiful piece-of-art wand. It’s like it belonged to some kind of satanic antique dealer.”

Whoever its former owner was, its next owner was clear. “I just had to have it,” Mr. Wainwright said. (The price, as well as he could recall, was “a few hundred bucks.”) Make that mostly clear, since it was technically a birthday present.

“Getting married, I am now keenly aware that most of the things I buy are also for me,” he said. “It’s his magic wand, but I am definitely privy to its powers as well, hopefully. We share the magic, O.K.?”

And he would say he needs it.

“It’s funny,” he said, “because when you’re a child, you really believe in the power of a magic wand, but you don’t need any of that magic then. Really, it’s when you get older, and you don’t believe in it anymore, that you need magic.”

That said, the wand has yet to be pressed into use, leading a largely symbolic or decorative existence on their coffee table.

“I am very respectful of the dark arts,” Mr. Wainwright said. “I mean that quite seriously, and I don’t like to mess around with black magic. I’m not an Aleister Crowley type.”

Above all, don’t expect him to be attempting spells gleaned from Hogwarts.

“I don’t like Harry Potter, and I don’t agree with Harry Potter,” he said. “I don’t think adults should be reading that stuff. Whenever I see someone reading Harry Potter on the subway, I think, ‘God, if they only knew what they looked like.’ ”

Then again, one of the unexpected joys of turning 40 is finding a liberating level of indifference about what you might look like — a freedom that no magic spell could ever conjure.

Correction:

The Possessed column last Sunday, about the rapidly approaching 40th birthday of the singer-songwriter Rufus Wainwright, on July 22, referred incorrectly to another well-known singer-songwriter, Leonard Cohen. Mr. Cohen is very much alive and, in fact, will turn 79 on Sept. 21; it is not the case that he is “the late Leonard Cohen.” (For the record: Mr. Cohen is currently on tour in Europe, with a performance scheduled in Brussels today.)

A version of this article appears in print on , on Page ST9 of the New York edition with the headline: From the Middle Ages To the Middle-Aged. Order Reprints | Today’s Paper | Subscribe